Statistical data are a key asset in today’s society, and an essential tool in supporting the most relevant decision-making processes, both at the public and private level, and in carrying out analyses and research.

Statistical data are therefore of interest to public and decision-makers, policy-makers, economic agents, analysts and researchers, paving the way for all individuals to gain more awareness of their citizenship.

Statistical data is only truly useful if it is credible and of high quality particularly as regards accuracy and timeliness.

In order to ensure quality dimensions, statistical producers are required to establish a commitment between rigor and swiftness as regards data released.

This commitment often gives rise to the need to conduct data revisions.

The need for revisions may also stem from the introduction of methodological improvements or the updating of statistical standards often decided on at international level.

Transparency, which must underlie the production and dissemination of official statistics, thus requires a detailed clarification of the Revisions policy.

The document on the revisions policy set out by Statistics Portugal, hereby presented, seeks to clarify the key factors of a revision, the typology of revision that may occur and the dimensions governing a revision’s analysis. It also explains the General and Operational Principles of the revisions policy that Statistics Portugal will consolidate in the future.